Screen doors, storm doors and the like, are utilized on millions of homes to provide fresh air, weather protection, and security, etc. The door typically includes a means for closing the door such as a spring or piston assembly or the like.
A popular means for controlling the door position utilizes a piston assembly which typically includes a cylindrical tube attached at one end to a bracket connector on the door. The inner surface of the cylindrical tube generally includes a spring loaded piston attached to a reciprocating connecting rod which extends from the piston and out of the tube. The end of the connecting rod opposite to the end carried and connected within the cylindrical tube typically is attached to a bracket which is connected to the door frame. When the door is opened, the connecting rod is pulled from the cylindrical tube, causing the piston to travel within the inner surface of the cylinder and thereby compress a spring coiled between an inner wall of the cylinder and the piston. When the door is released, energy stored within the spring pushes against the surface of the piston, causing it to slide within the cylinder and the connecting rod is drawn back within the cylindrical tube thereby closing the door. The retracting momentum of the piston is typically cushioned by compression of fluid such as air or oil inside the cylinder tube to create a damping resistance opposite the force that propels the door to close for better control of the speed and force at which the door closes.
Many different devices have been invented in order to maintain the door in a certain position, i.e., partially or completely open. One such device is a hold-open washer which has an aperture through which the connecting rod extends. The hold-open rod must be manually set once the door is opened at a position along the connecting rod. After the door is released, the connecting rod begins to be drawn back within the cylinder and is stopped when the hold-open washer makes contact with the end of the cylinder, binding the hold-open washer against the piston rod. The door will remain held in place until the door is opened and the hold-open washer is manually repositioned transversely along the connecting piston rod and away from the cylindrical tube.
U.S. Pat. No. 3,708,825 relates to a door check and door stop combination. The door check is made up of a pneumatic cylinder and piston which control the rate at which the door closes to prevent the door from slamming. A stop is attached to the distal end of the piston rod and lies along the side of the cylinder. The stop is made of a sheet material and has an aperture through it which receives the cylinder. The stop has a handle which may be engaged by the user's hand to move the stop from position in engagement with the cylinder.
U.S. Pat. No. 4,639,969 relates to door closer mechanism for attachment to, or incorporation into, a standard spring type door closer, or for use with a standard spring type door closer. A reversible pawl and ratchet assembly operating on a rod between the door and door casing allows the door to ratchet open where it is held by the pawl until a slight closing pull or push on the door reverses action of the pawl and allows the door to close. While the door is closing or is fully closed, reopening of the door resets the pawl for again holding the door open as desired.
U.S. Pat. No. 4,815,163 relates to a storm door lock apparatus set forth wherein a clamp is secured to an associated screen-door type closure member that further secures a slidable rod mounted with an abutment surface for actuation by a user with a pivoted lever at the other end of said rod for canting about a piston rod associated with a door closure. Additionally, a generally “L” shaped link is securable to the abutment member for allowing engagement and access by a user.
U.S. Pat. No. 5,575,513 relates to a receptacle for propping the cylinder of a cylinder-and-plunger strut in extended position of the strut includes two side-by-side cylindrical chambers, one being of a size to embrace the jack plunger rod but not the jack cylinder and the other chamber being of a size to slide over the jack cylinder, which chambers are interconnected by a slot sufficiently narrower than the jack plunger rod to enable the receptacle to move into a position embracing the jack plunger rod by snap action, and the larger chamber being of a size to slide lengthwise over the cylinder and having in it a lengthwise slot sufficiently narrow so as not to be able to pass the cylinder through it but sufficiently wide to pass the plunger rod through it.
U.S. Pat. No. 5,592,780 relates to an apparatus for controlling the position of a door suitable for use in association with door closing piston assemblies having a spring-biased reciprocable door closing piston rod and a latch plate transversely slidable along the length of the piston rod.
U.S. Pat. No. 5,659,925 relates to a holding mechanism attached to a generic door closing cylinder.
There are various disadvantages inherent in all of the prior art devices. To the Applicant's knowledge, none can be automatically locked open and released by simply moving the door without manual intervention. The prior art devices are often rather clumsy to manipulate when attempting to set or release a latch. Other disadvantages of the prior art devices are that they are rather complicated, hard to maintain, and expensive to produce.